Problem: Solve for $x$ and $y$ using substitution. ${-2x-3y = 0}$ ${y = x+5}$
Explanation: Since $y$ has already been solved for, substitute $x+5$ for $y$ in the first equation. ${-2x - 3}{(x+5)}{= 0}$ Simplify and solve for $x$ $-2x-3x - 15 = 0$ $-5x-15 = 0$ $-5x-15{+15} = 0{+15}$ $-5x = 15$ $\dfrac{-5x}{{-5}} = \dfrac{15}{{-5}}$ ${x = -3}$ Now that you know ${x = -3}$ , plug it back into $\thinspace {y = x+5}\thinspace$ to find $y$ ${y = }{(-3)}{ + 5}$ $y = 2$ You can also plug ${x = -3}$ into $\thinspace {-2x-3y = 0}\thinspace$ and get the same answer for $y$ : ${-2}{(-3)}{ - 3y = 0}$ ${y = 2}$